Sampling plans are widely used in manufacturing environments in order to determine whether items are being manufactured at a desired quality level. In order to construct a sampling plan, the ANSI/ASQ Z1.9 standard generally is used. The ANSI/ASQ Z1.9 standard is a collection of sampling plans presented in tabular and graphical form. In order to construct a sampling plan, the ANSI/ASQ Z1.9 standard is studied, and a sampling plan which best matches a desired sampling plan is selected.
Unfortunately, in using the ANSI/ASQ Z1.9 standard, the user may be bound to those sampling plans that are set forth in the standard. In particular, specific values of error rates, power, sample size and other parameters may be forced upon a user because the tables may not include the exact criteria that are desired by a given user.
Moreover, because the ANSI/ASQ Z1.9 standard uses test procedures that are based on a non-central t distribution, it may be difficult for the user to interpolate or extrapolate between tables of the standard. Notwithstanding these difficulties, the ANSI/ASQ Z1.9 standard continues to be widely used in constructing sampling plans for items that are manufactured.